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    <title>Document</title>
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    <script>
        console.log( typeof 123 === "number")
                console.log(a);
        var a = 10;
        console.log( (2==true)+1 )
        console.log(typeof typeof 123456)
        var a=Boolean("2" == "19")
        var _myName=12
        console.log(a)
        var a = 10; 

        function test(a){
          a -=3;
        } 

        test(a); 

        console.log(a);
        var num1=1;   
         function testf1(){
          num1=2;  
          var num1;
          alert(num1); 
         }
         function testf2(){
          alert(num1); 
         }
           testf1();
           testf2();
        console.log("1" + '1')
        for(var i = 1; i <= 5; i++){   

        if(i % 3 == 0){        continue    }

        } 

        console.log(i)
        var str="";
        var i=1;
        while(i<=10){
            if(i%2){
                str+=i+'';
            }
            i++;
        }
        document.write(str+'<br>')
    </script>
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